Short-term detergent treatment will be used as an alternative to long-term glycerination to investigate the roles of Mg, ATP, and Ca on tension regulation in smooth muscle. The proposed research involves: 1) assessing the effects of the detergent treatment by assaying the muscles for actomyosin content and calcium binding; 2) systematically determining the relationships between tension and the concentrations of Mg ions, ATP and Ca ions; 3) studying the effects on these relationships of interventions known to affect actomyosin activity, such as changes in ionic strength or pH; 4) investigating some of the mechanical properties with particular reference to the possible occurrence of rigor; 5) correlation of the effects of various concentrations of Mg ions, ATP and Ca ions with morphological data obtained with the electron microscope.